MgO冷陰極からの放出電子の初速度の過渡的変化

抄録

The relation of the change of emission current in starting process or of the transient change of sustained emission of unstable MgO cathode to the initial velocity distribution of electrons is examined by pulsive-retarding field method and cinema-graphic method.
Prior to MgO cathode emission being started by electron bombardment, the surface potential rises suddenly, and when the noise current, which is formed by the group of low velocity electrons, reaches a certain level, the emission starts suddenly. The self-sustained emission becomes steady after fluctuation of a short duration. The start of the emission seems to be initiated by local discharge on the surface of MgO layer.
The self-sustained emission comprises three components: the first is of above 10 kilo-cycle and is independent of the velocity distribution; the second is the flicker noise with varying velocity distribution; the third is of accidental nature, arising from ever changing emission surface.
Method for reducing the fluctuation of emission are discussed.